Generate ViewStateProvider for presenters in nested classes

[Svechnikov]

Currently, moxy compiler doesn't generate correct ViewStateProvider classes for nested presenters, which leads to a NPE at runtime when trying to access view state.

By "nested" I mean defined in an interface or another class:

class SomeClass {
    class MainPresenter : MvpPresenter<MainView>() {
        ...
    }
}

or

interface SomeInterface {
    class MainPresenter : MvpPresenter<MainView>() {
        ...
    }
}

We can easily fix this by taking into account enclosing classes.

The proposed solution doesn't break anything and works for both nested and non-nested presenters.

[Svechnikov]

Hi Alexey!

You should add a unit test for the new feature you're proposing

Will do.

Why did you delete MainPresnter.kt?

Sorry, I was experimenting and I deleted it by accident :) I'll bring it back.